to take the warping out of your mat... lay it flat in the driveway or cement patio on a hot day let the sun do the work if the warping isn't bad that should work. or what I have done with my badly warped one is put it in the jaguzzi, taken it out after couple of hours and put piece of plywood on it on the floor and weighed it down with some old phone books i had and a small table up side down on it . That was 11 years ago and it is still going strong. I thought I would at least try cause I couldn't use it the way it was anyway. I was just happy it worked.